Ruby-on-rails 将数组传递给 hidden_​​field ROR

Passing an array into hidden_field ROR

提问by JZ.

I'm trying to pass an array into a hidden_field.

我正在尝试将数组传递到 hidden_​​field 中。

The following User has 3 roles [2,4,5]

以下用户有 3 个角色 [2,4,5]

>> u = User.find_by_login("lesa")
=> #<User id: 5, login: "lesa", email: "[email protected]", crypted_password: "0f2776e68f1054a2678ad69a3b28e35ad9f42078", salt: "f02ef9e00d16f1b9f82dfcc488fdf96bf5aab4a8", created_at: "2009-12-29 15:15:51", updated_at: "2010-01-06 06:27:16", remember_token: nil, remember_token_expires_at: nil>
>> u.roles.map(&:id)
=> [2, 4, 5]

Users/edit.html.erb

用户/edit.html.erb

<% form_for @user do |f| -%>
<%= f.hidden_field :role_ids, :value => @user.roles.map(&:id) %>

When I submit my edit form, I receive an error: ActiveRecord::RecordNotFound in UsersController#update "Couldn't find Role with ID=245"

当我提交我的编辑表单时，我收到一个错误：ActiveRecord::RecordNotFound in UsersController#update“找不到 ID=245 的角色”

How can I pass an array into the hidden_field?

如何将数组传递到 hidden_​​field 中？

回答by Grant Hutchins

I would use this technique.

我会使用这种技术。

<% @user.roles.each do |role| %>
    <%= f.hidden_field :role_ids, :multiple => true, :value => role.id %>
<% end %>

:multipleadds both the []to the end of the name attribute and multiple="multiple"to the input element, which is ideal. Rails uses this internally when it generates inputs for arrays, such as in fields_for.

:multiple将 加到[]name 属性的末尾和multiple="multiple"input 元素，这是理想的。Rails 在为数组生成输入时在内部使用它，例如 in fields_for。

Unfortunately it is not well-documented. I'm going to look into fixing this.

不幸的是，它没有得到很好的记录。我要研究解决这个问题。

回答by Matteo Melani

The only thing that works for me (Rails 3.1) is using hidden_field_tag:

唯一对我有用的东西（Rails 3.1）是使用 hidden_​​field_tag：

<% @users.roles.each do |role| %>
    <%= hidden_field_tag "user_role_ids[]", role.id %>
<% end %> 

回答by jamuraa

Try:

尝试：

 <% @user.roles.each_with_index do |role| %>
    <%= f.hidden_field "role_ids[]", :value => role.id %>
 <% end %>

回答by mendokusai

using Rails 4.2.6

使用 Rails 4.2.6

I was able to use

我能够使用

<% @user.roles.each do |role|
  <%= f.hidden_field :role_ids, :id => role.id, :value => role.id, :multiple => true %>
<% end %>

which rendered:

其中呈现：

<input id="12345" value="12345" multiple="multiple" type="hidden" name="role_form[role_ids][]">

trying to use hidden_field_tagor the 'role_ids[]'the param details were not being included in my form_params.

尝试使用hidden_field_tag或'role_ids[]'参数详细信息未包含在我的form_params.

This didn't work:

这不起作用：

<% @user.roles.each do |role|
  <%= hidden_field_tag 'role_ids[]', role %>
<% end %>

because it renders:

因为它呈现：

<input type="hidden" name="role_ids[]" id="role_ids_" value="12345">

and is seen by the controller outsideof the form params.

并且被表单参数之外的控制器看到。

回答by makevoid

try with:

尝试：

<%= f.hidden_field :role_ids, :value => @user.roles.map(&:id).join(", ") %>

edit: note - you'll need to do ids.split(", ")in your controller to convert them from a string into an array

编辑：注意 - 您需要ids.split(", ")在控制器中将它们从字符串转换为数组

回答by richardsonae

I realize the original question involved a Rails form_forform, but I just encountered this problem while trying adding a hidden field to a form_tagform. The solution is slightly different.

我意识到最初的问题涉及一个 Railsform_for表单，但我在尝试向form_tag表单添加隐藏字段时遇到了这个问题。解决方案略有不同。

The hidden_field_tagkept converting my ids to a space-separated string, like "1 2 3", not the array of ["1", "2", "3"]that I wanted. According to the docs, this is a known problem with hidden_field_tag. This is the approach that ended up working for my Rails 6 form_tagform:

在hidden_field_tag不停转换我的ID，以一个空格分隔的字符串，如"1 2 3"，而不是数组的["1", "2", "3"]，我想。根据文档，这是hidden_field_tag. 这是最终适用于我的 Rails 6form_tag表单的方法：

In the view:

在视图中：

<%= hidden_field_tag :role_ids, my_role_ids_array %>

In the controller:

在控制器中：

role_ids = params[:role_ids].split(' ').map(&:to_i)